Thalamic paraventricular nucleus mediates orexinergic neurons-induced promotion of emergence from general anesthesia in mice: evaluation using optogenetics method / 中华麻醉学杂志

Objective To evaluate whether the thalamic paraventricular nucleus mediates orexiner-gic ( orexin ) neurons-induced promotion of emergence from general anesthesia by using the optogenetics method in mice. Methods Twenty healthy male Hcrt-cre mice, aged 8-10 weeks, weighing 20-25 g, were divided into 4 groups ( n=5 each) using a random number table method: retrograde labeled viruses channelrhodopsin group ( R group) , anterograde labeled viruses channelrhodopsin group ( A group) , retro-grade labeled viruses control group ( RC group ) , and anterograde labeled viruses control group ( AC group) . The optogenetics technique was used in each group. Anesthesia was induced and maintained through inhaling 1％ isoflurane and pure oxygen 1. 0 L∕min. Electroencephalogram was monitored througout the procedure with the PowerLab monitoring system. The burst suppression ratio ( BSR) was recorded at 1 min before light stimulation and during light stimulation. Results Compared with RC group or the baseline at 1 min before light stimulation, the BSR was significantly decreased during light stimulation in R group ( P<0. 05) . Compared with AC group or the baseline at 1 min before light stimulation, the BSR was signifi-cantly decreased during light stimulation in group A ( P<0. 05) . Conclusion Optogenetics technique ap-plication once again confirms that orexin neurons can promote emergence from general anesthesia through thalamic paraventricular nucleus in mice.

Neural Mechanisms and Delayed Gastric Emptying of Liquid Induced Through Acute Myocardial Infarction in Rats / Mecanismos Neurais e Retardo do Esvaziamento Gástrico de Liquido Induzido no Infarto Agudo do Miocárdio em Ratos

Background: In pathological situations, such as acute myocardial infarction, disorders of motility of the proximal gut can trigger symptoms like nausea and vomiting. Acute myocardial infarction delays gastric emptying (GE) of liquid in rats. Objective: Investigate the involvement of the vagus nerve, α 1-adrenoceptors, central nervous system GABAB receptors and also participation of paraventricular nucleus (PVN) of the hypothalamus in GE and gastric compliance (GC) in infarcted rats. Methods: Wistar rats, N = 8-15 in each group, were divided as INF group and sham (SH) group and subdivided. The infarction was performed through ligation of the left anterior descending coronary artery. GC was estimated with pressure-volume curves. Vagotomy was performed by sectioning the dorsal and ventral branches. To verify the action of GABAB receptors, baclofen was injected via icv (intracerebroventricular). Intravenous prazosin was used to produce chemical sympathectomy. The lesion in the PVN of the hypothalamus was performed using a 1mA/10s electrical current and GE was determined by measuring the percentage of gastric retention (% GR) of a saline meal. Results: No significant differences were observed regarding GC between groups; vagotomy significantly reduced % GR in INF group; icv treatment with baclofen significantly reduced %GR. GABAB receptors were not conclusively involved in delaying GE; intravenous treatment with prazosin significantly reduced GR% in INF group. PVN lesion abolished the effect of myocardial infarction on GE. Conclusion: Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN. .

Fundamento: Distúrbios da motilidade do intestino proximal no infarto agudo do miocárdio podem desencadear sintomas digestivos como náuseas e vômitos. O infarto do miocárdio ocasiona retardo do esvaziamento gástrico (EG) de líquido em ratos. Objetivo: Investigar se existe a influência do nervo vago (VGX), adrenoreceptores α-1, receptores GABAB do sistema nervoso central e participação do núcleo paraventricular (NPV) do hipotálamo no esvaziamento gástrico (EG) e complacência gástrica (CG) em ratos infartados. Métodos: Ratos Wistar (n = 8-15) foram divididos em: grupo infarto (INF), sham (SH) e subdivididos. O infarto foi realizado por ligadura da artéria coronária descendente anterior. A complacência gástrica foi estimada com curvas pressão-volume. Realizada vagotomia por secção dos ramos dorsal e ventral. Para verificar a ação dos receptores GABAB foi injetado baclofeno por via intra ventrículo-cerebral. Simpatectomia química foi realizada com prazosina intravenosa (iv), e na lesão do núcleo paraventricular do hipotálamo foi utilizada corrente elétrica de 1mA/10s, com esvaziamento gástrico determinado por medição da retenção gástrica (% RG) de uma refeição salina. Resultados: Não houve diferença significativa na CG. A vagotomia (VGX) reduziu significativamente a %RG; no grupo INF, o tratamento intra ventrículo-cerebral (ivc) com baclofeno reduziu significativamente a % RG; não houve conclusivamente envolvimento dos receptores GABAB em retardar o EG; o tratamento intravenoso com prazosina reduziu significativamente a %RG no grupo INF. A lesão do NPV aboliu o efeito do infarto do miocárdio no EG. Conclusão: O nervo vago, receptores α-adrenérgicos e núcleo paraventricular estão envolvidos no retardo do esvaziamento gástrico no infarto agudo do miocárdio em ratos. .

NMDA receptors in central medial thalamus participate in propofol-induced unconsciousness / 天津医药

Objective To investigate the role of NMDA receptors in central medial thalamus (CMT) in the unconscious?ness induced by general anesthesia. Methods A total of 60 rat models for microinfusion were assigned into 4 groups (n=15 for each group). After induction with propofol, 10 mmol/L (NMDA10 group), 20 mmol/L (NMDA 20 group) and 40 mmol/L (NMDA40 group) of NMDA and normal saline (group C) with equal volume were microinfused into CMT. The incidence of purposeful movement and recovery time of righting reflex were observed in each group respectively. Infusion sites were local?ized by histological method. Results When the microinfusion site localized within CMT, comparing with group C, the recov?ery time of righting reflex reduced notably in three NMDA groups (P0.05). Conclusion Microinfusion of NMDA agonist into CMT reverses propofol anesthesia, indicating that NMDA receptor in CMT may contribute to the propofol-induced unconsciousness.